1 # SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
2 %YAML 1.2
3 ---
4 $id: http://devicetree.org/schemas/i2c/i2c-demux-pinctrl.yaml#
5 $schema: http://devicetree.org/meta-schemas/core.yaml#
6
7 title: Pinctrl-based I2C Bus Demultiplexer
8
9 maintainers:
10 - Wolfram Sang <wsa+renesas@sang-engineering.com>
11
12 description: |
13 This binding describes an I2C bus demultiplexer that uses pin multiplexing to
14 route the I2C signals, and represents the pin multiplexing configuration
15 using the pinctrl device tree bindings. This may be used to select one I2C
16 IP core at runtime which may have a better feature set for a given task than
17 another I2C IP core on the SoC. The most simple example is to fall back to
18 GPIO bitbanging if your current runtime configuration hits an errata of the
19 internal IP core.
20
21 +-------------------------------+
22 | SoC |
23 | | +-----+ +-----+
24 | +------------+ | | dev | | dev |
25 | |I2C IP Core1|--\ | +-----+ +-----+
26 | +------------+ \-------+ | | |
27 | |Pinctrl|--|------+--------+
28 | +------------+ +-------+ |
29 | |I2C IP Core2|--/ |
30 | +------------+ |
31 | |
32 +-------------------------------+
33
34 allOf:
35 - $ref: /schemas/i2c/i2c-controller.yaml#
36
37 properties:
38 compatible:
39 const: i2c-demux-pinctrl
40
41 i2c-parent:
42 $ref: /schemas/types.yaml#/definitions/phandle-array
43 items:
44 maxItems: 1
45 description:
46 List of phandles of I2C masters available for selection. The first one
47 will be used as default.
48
49 i2c-bus-name:
50 $ref: /schemas/types.yaml#/definitions/string
51 description:
52 The name of this bus. Also needed as pinctrl-name for the I2C parents.
53
54 required:
55 - compatible
56 - i2c-parent
57 - i2c-bus-name
58
59 unevaluatedProperties: false
60
61 examples:
62 - |
63 #include <dt-bindings/gpio/gpio.h>
64 #include <dt-bindings/interrupt-controller/irq.h>
65
66 gpioi2c2: i2c-9 {
67 #address-cells = <1>;
68 #size-cells = <0>;
69 compatible = "i2c-gpio";
70 scl-gpios = <&gpio5 5 (GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN)>;
71 sda-gpios = <&gpio5 6 (GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN)>;
72 i2c-gpio,delay-us = <5>;
73
74 // The I2C controller must have its status "disabled". The I2C bus
75 // demultiplexer will enable it at runtime when needed.
76 status = "disabled";
77 };
78
79 iic2: i2c@e6520000 {
80 reg = <0xe6520000 0x425>;
81 pinctrl-0 = <&iic2_pins>;
82 // The pinctrl property for the parent I2C controller needs a pinctrl
83 // state with the same name as i2c-bus-name in the I2C bus demultiplexer
84 // node, not "default"!
85 pinctrl-names = "i2c-hdmi";
86
87 clock-frequency = <100000>;
88
89 // The I2C controller must have its status "disabled". The I2C bus
90 // demultiplexer will enable it at runtime when needed.
91 status = "disabled";
92 };
93
94 i2c2: i2c@e6530000 {
95 reg = <0 0xe6530000 0 0x40>;
96 pinctrl-0 = <&i2c2_pins>;
97 // The pinctrl property for the parent I2C controller needs a pinctrl
98 // state with the same name as i2c-bus-name in the I2C bus demultiplexer
99 // node, not "default"!
100 pinctrl-names = "i2c-hdmi";
101
102 clock-frequency = <100000>;
103
104 // The I2C controller must have its status "disabled". The I2C bus
105 // demultiplexer will enable it at runtime when needed.
106 status = "disabled";
107 };
108
109 // Example for a bus to be demuxed. It contains various I2C clients for
110 // HDMI, so the bus is named "i2c-hdmi":
111 i2chdmi: i2c-mux3 {
112 compatible = "i2c-demux-pinctrl";
113 i2c-parent = <&iic2>, <&i2c2>, <&gpioi2c2>;
114 i2c-bus-name = "i2c-hdmi";
115 #address-cells = <1>;
116 #size-cells = <0>;
117
118 ak4643: codec@12 {
119 compatible = "asahi-kasei,ak4643";
120 #sound-dai-cells = <0>;
121 reg = <0x12>;
122 };
123
124 composite-in@20 {
125 compatible = "adi,adv7180";
126 reg = <0x20>;
127
128 port {
129 adv7180: endpoint {
130 bus-width = <8>;
131 remote-endpoint = <&vin1ep0>;
132 };
133 };
134 };
135
136 hdmi@39 {
137 compatible = "adi,adv7511w";
138 reg = <0x39>;
139 interrupt-parent = <&gpio1>;
140 interrupts = <15 IRQ_TYPE_LEVEL_LOW>;
141 clocks = <&cec_clock>;
142 clock-names = "cec";
143
144 avdd-supply = <&fixedregulator1v8>;
145 dvdd-supply = <&fixedregulator1v8>;
146 pvdd-supply = <&fixedregulator1v8>;
147 dvdd-3v-supply = <&fixedregulator3v3>;
148 bgvdd-supply = <&fixedregulator1v8>;
149
150 adi,input-depth = <8>;
151 adi,input-colorspace = "rgb";
152 adi,input-clock = "1x";
153
154 ports {
155 #address-cells = <1>;
156 #size-cells = <0>;
157
158 port@0 {
159 reg = <0>;
160 adv7511_in: endpoint {
161 remote-endpoint = <&lvds0_out>;
162 };
163 };
164
165 port@1 {
166 reg = <1>;
167 adv7511_out: endpoint {
168 remote-endpoint = <&hdmi_con_out>;
169 };
170 };
171 };
172 };
173 };
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.